Field
The present invention relates to a vehicle engine which is provided with an air cleaner of the configuration that the interior of a cleaner case is divided into an unpurified chamber and a purified chamber by a bulkhead holding a cleaner element, a main fuel injection valve for injecting fuel into an intake passage that makes communication between an intake port provided in a cylinder head of an engine body and the purified chamber, and a secondary fuel injection valve for injecting fuel into the intake passage along a flow direction in the intake passage on an upper side in stream than the main fuel injection valve, and particularly, to an improvement in a fuel supply structure.
Description of the Related Art
As disclosed in JP Patent No. 4598838 (patent literature 1), there has already been known a vehicle engine in which fuel is enabled to be injected into an intake passage making communication between a purified chamber of an air cleaner and an intake port in a cylinder head, from a main fuel injection valve on a downstream side in a flow direction in the intake passage and from a secondary fuel injection valve on an upstream side in the flow direction.
In patent literature 1, a main fuel injection valve is attached to a throttle body arranged outside the air cleaner, while the secondary fuel injection valve is housed in the air cleaner or attached to the air cleaner from the outside of the same, to reduce restrictions on the freedom in piping fuel pipes to the main fuel injection valve and the secondary fuel injection valve. However, where the air cleaner is configured to be large in order to accommodate required capacity, the main fuel injection valve and the secondary fuel injection valve are housed together with the throttle body and the like in the air cleaner. This can help avoid a dimensional increase of an intake device that would result from securing, outside the air cleaner, the space required to arrange parts forming the air passage such as the throttle body and the like, the main fuel injection valve and the secondary fuel injection valve. In this case, it is desirable that the fuel piping for supplying fuel to the main fuel injection valve and the secondary fuel injection valve be of the structure which decrease the number of required parts, and which can be arranged in an air cleaner having a spatial restriction.